1. Field of the Invention
This invention relates to the field of templates and overlays for keys and keypads and, more particularly, to overlays for a touchtone telephone keypad.
2. Description of the Related Art
Keypads have been in use for many years on a wide variety of equipment, such as calculators, both mechanical and electrical or electronic, touchtone telephones, computer keyboards and many other devices. Commonly referred to as "numeric" or "alphanumeric"--the latter because it designates the use of keys with both alphabetical and numeric functions--an alphanumeric keypad is generally understood to encompass other symbols as well, such as the star or asterisk (*) and the pound or number sign (#) on a telephone keypad. Overlays for alphanumeric keypads have been developed for protection (to protect the keys and the underlying circuitry from vandalism, dirt and other environmental damage), for key enhancement, such as enlarging the effective touch area for key manipulation, and for numerous other purposes.
The known related art is exemplified by patents U.S. Pat. No. 3,491,221 to Zamarra and U.S. Pat. Nos. 4,438,300 and 4,555,600, both to Morse, all of which are exclusively concerned with protecting telephone keypads from dirt, liquid spills or vandalism. Insofar as is known, the existing related art provides no means for adapting telephone keypads to new uses. While recent technical advances have created new telephone features and a host of telephone services, such as the so-called "900"-number services, very little development of an innovative nature has occurred in the field to which the present invention relates.